Friction clutches for transmitting torques between a drivable rotor and an element to be driven by the rotor are known, allowing parts that are to be coupled to one another, such as disk-type clutch components, to be selectively separated or connected, in particular, by nonpositive engagement.
Friction clutches of this kind can be designed as magnetic clutches, which comprise an electromagnet arrangement having a coil former or wire coil, which can be connected to an electric voltage source and energized, and a coil support composed of magnetically conductive material.
These also include arrangements which additionally have permanent magnets, by means of the magnetic action of which, when the electromagnet is not exerting a magnetic effect, a movable clutch element is attracted to a mating section, counter to a spring force or the like, for example, and these components are connected nonpositively for torque transmission. By energizing the electromagnet, it is then possible, by means of the magnetic field produced, to attenuate or cancel out the effect of the permanent magnet to such an extent that the friction clutch disengages, with the movable clutch element leaving the position of nonpositive engagement.
These clutches are used in vehicles, for example.
The disadvantage with the arrangements described is the comparatively high outlay involved in the manufacture of such clutches and the components thereof.